In the drilling of wells, such as oil and gas wells, it is desirable to rack the stands of drill pipe and drill collars in racking means in the derrick or beneath the floor of the derrick. Such racking apparatus necessitates the movement of successive pipe stands between racked positions and a position at the center of the derrick, and the pipe must be transferred between such positions by suitable supporting means engageable beneath the usual shoulder provided by the tool joint or coupling end of the pipe.
To conserve space in the rack, the pipe is racked in close, side by side relation in sequence, by pipe lifting and positioning means such as that disclosed in U.S. Pat. No. 3,561,811, granted Feb. 9, 1971, or in the companion application for U.S. Patent Ser. No. 526,207, filed Nov. 22, 1974. In either case, the pipe is supported in a head which engages beneath the upset or shoulder of the tool joint to support the pipe and move it during the racking and unracking operations.
In order to constrain the pipe against swinging in the derrick and to position the pipe with respect to the rack and the center of the derrick a positioning guide means may be employed, for example, as disclosed in the aforesaid companion application Ser. No. 526,207. Such positioning guide means must accommodate a variety of pipe sizes, such as drill pipe and larger drill collars, as well as, at other times different sized drill pipe and drill collars.